Sheet feeding devices for hectographic duplicating machines



April 2, 1957 R. BROWN SHEET FEEDING DEVICES FOR HECTOGRAPHICDUPLICATING MACHINES d on. 9, 1955 3 Sheets-Sheet 1 File I/vvcvvr'aklPaulvp BRoww April 2, 1957 v R. BROWN 1 swam FEEDING uzvrcss FORHECTOGRAPHIC numcmuc mamas Filed on. 9, 1953 s Sheets-Sheet 2 Fig.2.

SHEET FEEDING DEVICES FOR HECTOGRAPHIC DUPLICATING MACHINES Filed Oct.9, 1953 R. BROWN April 2, 1957 3 Sheets-Sheet 3 United States PatentSHEET FEEDING DEVICES FOR HECTO- GRAPHIC DUPLICATING MACHINES RolandBrown, London, England, assignor to Block &

Anderson Limited, London, England, a British com- Pally ApplicationOctober 9, 1953, Serial No. 385,210 Claims priority, application GreatBritain April 23, 1953 11 Claims. (Cl. 101-1325) The invention relatesto sheet feeding devices, and is concerned more particularly with sheetfeeding mechanism for rotary duplicating machines.

In rotary duplicating machines of the spirit type, in which copies aretaken from a hectographic master sheet wrapped round a rotary drum, thecopy sheets must be fed singly to the bight between the printing couple,comprising the drum and a counter-pressure roller, after being moistenedwith a volatile solvent for the hectographic ink. Machines of this typeare either designed for hand feeding of the sheets, or are provided withautomatic feeding mechanism whereby the sheets are fed singly from astack to the bight between the drum and the counter-pressure roller atthe correct instant by means operated in timed relation with the rotarydrum. Such sheet feeding mechanism is often relatively complicated andtherefore expensive to install and service and may account for aconsiderable proportion of the total cost of the machine.

An object of the present invention is to provide sheet feeding mechanismfor rotary duplicating machines, including hectographic machines, ofcomparatively simple construction, having a minimum number of parts andhaving the advantages of simplicity in construction and installation.

A further object of the invention is to provide, in a hectographicduplicating machine employing direct damping of the copy sheets by adamping pad, novel sheet feeding mechanism positioned at the deliveryend of a feed tray for the copy sheets and intermittently driven fromthe printing drum.

A further object of the invention is to provide, in a rotary duplicatingor the like machine, automatic sheet feeding mechanism comprising twosheet feeding devices in tandem, the first feeding means having aquickly releasable or non-positive coupling to the driving means so thatthe automatic feed can be de-coupled without loss of time so that themachine may be adapted for manual feed or automatic feed as desiredwithout the removal or interchange of working parts.

According to the invention, in a hectographic duplicating machine havingdamping pad means for direct moistening of the copy sheets, sheetfeeding mechanism includes means for aligning the side edges of copysheets and a rotary feeding couple positioned next before the dampingpad means in the line of feed of the sheets from a stack to the printingcouple and having frictional contact with the sheet over a central Zoneof small width with respect to the printing drum, the upper feedingelement of said couple being an idler roller of small diameter havingbearings therefor supported in the delivery end of the feed tray and thelower feeding element being a wheel of larger diameter than the idlerroller and having a shaft journalled in the machine frame, and meansincluding a one-way clutch coupling the wheel shaft of the drum forintermittently driving said feeding couple in timed relation with thedrum so that one forward feeding stroke is performed for each completerevolution of the drum.

2,787,211 Patented Apr. 2, 1957 According to a further feature of theinvention sheet feeding mechanism comprises a first sheet feeding meansreciprocated in timed relation with the movements of rotary drum foradvancing sheets singly from a stack towards the printing couple, and asecond sheet feeding means situated between the first feeding means andthe printing couple for guiding and further advancing the sheet towardsthe printing couple, the said latter sheet feeding means being situatedbefore the copy sheet damping means so that damping is commenced. afterthe sheet has been advanced by both of said sheet feeding means.

The second sheet feeding means also fulfills the function of obtainingcorrect register of the copy sheets with respect to the damping pad andthe printing couple, and for this purpose the timing of the feed strokesof the first and second feeding means is such that the leading edge ofeach copy sheet is first registered between the rotary members of thesecond feeding means and at the correct distance from the printingcouple before being further advanced by the said second feeding means.

Preferably also the motions of the damping means and of the sheetfeeding means next before the printing couple are relatively timed suchthat damping of the copy sheet is effected just after the leading edgeof the sheet has been gripped in the printing couple.

Preferably, the sheet feeding mechanism comprises frictional sheetfeeding means reciprocated in timed relation with the rotary drum, andmounted on a removable feed tray which retains and aligns the stack ofcopy sheets. In one form of the invention the tray is removable from themachine without the uncoupling of any driving means between the printingdrum and the said feeding means, whilst in another form a quicklyreleasable coupling is fitted allowing for automatic or hand feed of thecopy sheets from the stack as desired. Furthermore, the sheet feedmechanism comprises also a rotary feeding couple positioned between thesaid frictional sheet feed means and the rotary printing couple in theline of movement of the sheets, the feeding couple consisting of arotary feeding member intermittently driven in timed relationship withthe rotary drum, and a co-operating non-driven roller, the saidnon-driven roller being mounted on the feed tray so as to be removabletherewith when the tray or table is bodily removed from the machine.

The said rotary feeding member and its co-operating non-driven orcounter-pressure feed roller may be of comparatively small width inrelation to the width of the copy sheet, provided that the rotaryfeeding couple is centrally placed in the line of feed. Accordingly thesaid rotary feeding member is in the form of a wheel whose periphery iscovered with rubber or other material for providing a frictional grip onthe copy sheet. To provide additional guidance for the copy sheet apartfrom the traction of the rotary feeding couple acting symmetricallyalong the line of feed, adjustable guide blocks are preferably arrangedat each side of the feed tray to guide the side edges of the sheet. Thewheel may be of large diameter in relation to that of the non-drivenroller without making the feed mechanism unduly heavy, as would be thecase with a feed roller extending the full width of the machine. Alsothe comparatively large diameter of the wheel makes possible the use ofa convenient and simple type of linkage between the wheel shaft and thedrum. shaft for the intermittent drive as will be described below.

In a preferred arrangement as applied to hectographic duplicatingmachines having a damping pad extending across the operative width ofthe printing couple for applying a solvent across the entire width ofthe copy sheet beginning at a given determined distance from the leadingedge of the sheet hereinafter termed the undamped margin, the saiddamping pad is arrangedto be pivoted about an axisv parallel to that ofthe drum so as. to bev brought into and out of contact with the topsurface of the copy sheet at the appropriate times in the printingcycle, and sheet feeding mechanism is arranged for feeding sheets singlyfromv a. stack past the damping pad into the bight of the printingcouple, the said damping pad and the sheet feeding mechanism beingoperated in timed relationship with the movements, of the rotary drum,such that each, copy sheet is gripped by the printing couple before thedamping pad is brought into operation to contact the copy sheet.

An example of sheet feeding mechanism according to the invention willnow be described in more detail with reference to the accompanyingdiagrammatic drawings, wherein:

Figure 1 indicates a section transverse to the drum axis of a rotaryhectographic duplicating machine, and

Figure 2 shows a plan view of the machine showing the feed tray and suchother parts of the machine as are necessary for an understanding of theinvention.

Figure 3 is a sketch illustrating a releasable coupling which may beemployed to obtain the automatic drive to the frictional sheet feedingmeans reciprocated in the feed tray;

Figure 4 is a detail view on an, enlarged scale, being P t y a ion onthe plane IV--IV of Fig. 1 to. show a sliding guide: for paper widthadjustment, a spring clip device for the guide and a paper grip mountedon the guide and partly a section on the plane V-V of Fig. 1.

Figures 5 and 6 are respectively an axial section and a plan on anenlarged scale illustrating diagrammatically a ball clutch which may beused in the driving mechanism.

Referring now to the drawings, 1 indicates the righthand side frame ofthe machine and 1a the left-hand side frame, the front or feeding end ofthe machine being at the right-hand side of the drawing. This side framecomprises a casing having various integral bearing bushes cast thereinto receive, the bearings of, the various moving parts of: the machine,of which only those comprising the present invention will be referredto. 2 indicates the periphery of the rotary drum rotatable clockwiseabout the axis at 0, Whilst 3 indicates the counter-pressure rollorextending the full Width of the drum and formingtherewith the printingcouple. The drum is provided with a movable clip for retaining aprinting master wrapped round the periphery thereof (not shown). Thedetails of the arrangement of the printing couple and the clip and theoperating means therefor are well known in such machines and will not bereferred to herein.

A. damping pad 4. for moistening the copy sheet extends forwardly towithin. a short distance of the printing couple, and is mounted forpivoting movement about a horizontal axis. P by cam means which will bereferred to more fully hereinafter.

A removable feed tray 10 extends from the front of the machine and is.provided with means, which will be described later, for holding a stackof sheetsStl.

The. sheet feeding meansprovided by the invention for advancing the copysheets to the printing couple 2, 3 comprise; the following parts. Awheel 21, of small width compared with the drum, is secured. centrallyof a shaft 22 carried in hearings in the side. frames. of the machine,and is, intermittently driven as follows. A lever 23 is pivoted on afixed stud inthe side frame 1 of the machine at 24 so that its. upperend bears against a cam roller 25 carried on the left hand face of the.eccentric cam 15. The lower end of the lever 23 is. pivoted at 26 to alink 27, which is itself pivoted at 28 to another lever 29 pivoted abouta stud 30 secured to the side frame 1. The upper end [of the lever 29carries, a pin 31 movable in a slot 3 2 in a lever 33, which is coupledto the shaft 22 of the wheel 21 through any appropriate known type ofone-way clutch, for example a ball or roller clutch, so that onlycounter-clockwise motion is transmitted to thewheel', the lever 33 beingdecoupled from the. shaft whilst moving in the clockwise direction. Adetail of a suitable type of ball clutch is shown diagrammatically inFigures 5 and 6, wherein a ball is located in a cage formed by a loosesplit ring 121. A flanged ring 122 is keyed to the boss 123 of lever 33by screw and is radiu'sed at 124 to allow the ball to rotate and to runon the shaft 22 when the lever 33 is turned counterclockwise. When thelever is turned in the opposite direction the ball wedges between theshaft and the flat portion 126 of the flange which is split at 127.

The periphery of the wheel, 21 carries a tyre 34 of rubber or similarmaterial capable of alfording a frictional grip on the paper, andco-operates with a non-driven feed roller 35 carried in the feed tray 10to form a feeding couple. The feed tray has a funnel shaped dischargeend formed by an apron 36 of thin sheet metal extending transverselybetween the upturned sides 38 and 39 of the tray and fixed thereto bysuitable means such as screws or bolts. A gap 37 is cut in the frontedge of the apron, and the roller 35 is carried in bearings 40 in aspring plate 54 secured in cantilever fashion to the apron 36 by meansof rivets 55. This arrangement allows the roller to rest with a lightpressure on the periphery of the wheel 21 when the tray is in theposition shown, in the drawing. The bottom 41 of the tray is slotted at42 to allow the wheel 21 to project there; through and to make contactwith the roller 35. The fixed pad surface bar 43 which extends betweenthe side frames, is also slotted at 44 over a similar width toaccommodate the periphery of the wheel 21. The assemblyof the feed. tray10 complete with the reciprocating fric tion roller 5 and the non-drivenfeed roller 35 is received in, suitable guides in the side frames of themachine, and the forward edge of the tray rests on the-pad surfacecrossbar 43-which serves as a stationary paper guide as shown in Figure1.

Means, for obtaining the damping of the copy sheet in timed relationwith the drum motion are as follows:

The damping pad 4 is housed in known manner in a pad frame assembly 56which is mounted for pivotal movement about axis P and whose front endis downwardly biased by springs (not shown) anchored to the machineframe and to the pad frame assembly.

A cam disc 52 secured to the left-hand side of the drum shaftco-operates with a cam roller 58 secured to a lever 5-9, freely pivotedabout the axis P and upwardly biased by a spring 60 anchored to theframe at 61.

The left-hand end 57 of the pad frame has a lug 62. (Fig. 2) carrying anadjusting screw 63, the end of which bears downwardly against the lever59 under the tensionof the pad. frame springs, but: the tension ofspring 60 predominates to keep the pad frame normally in the raisedposition. Such adjusting screw provides for adjustment of the positionofthe pad frame with respect to lever. 59 and, therefore, of the timing ofthe pad frame motion as. will be clear from the description whichfollows. Copy sheets may be fed singly by hand to the feeding couple 21,35 which transfers them to the. printing couple in a manner to bedescribed later. It is preferable, however, to have automatic feed fromthe stack 50, and, for this. purpose, the following mechanism isprovided.

The tray 10'carries an automatically operated frictionalv sheet feedingmeans comprising. a friction feed roller 5- mounted at, the end 6 of acranked shaft 7, which; is supported for free pivoting movement aboutits axis on a sliding carriage 8. For this purpose the shaft 7 is pro,-vided with a pin 7a entering a bayonet slot 7b in a. bushing 13 so thatthey shaft 7 and roller 5 are easily removable: as a unit. The carriage8 is movable; along a guide rail. 9 rigidly secured to the right handside of the removable feed tray 10 by means of studs 11. The frictionfeed roller is coupled to the end- 6 of the, cranked. shaft throughv anyappropriate known form of one Way clutch, which in the present exampleis preferably a ratchetclutch, so that the feed roller is free torotate. only in, the. clockwise direction. The feed roller 5 and clutchare not shown in detail in the drawing. The friction feed roller 5, mayconsist of any convenient number of rubber discs mounted on a bushingwhich may be slipped over the shaft 6 and coupled to a clutch alreadymounted on the shaft 6. The Coupling between the roller assembly 5 andthe clutch may consist of a pin on the clutch engaging a hole in thefriction feed roller assembly. A striker bar 12 is also secured to thecarriage 8, and the complete assembly of carriage, cranked shaft,friction rollers and striker bar, is urged into the rest .position shownin the drawing by means of a spring 14 anchored between a part of thecarriage 8 and the fixed stud 11.

The friction roller feed mechanism above described is actuated by cammechanism which is operated in timed relation with the drum and whichconsists of the following parts. A plain eccentric cam 15 is secured tothe right-hand end of the drum shaft between the end of the drum and theside frame 1. A bell crank 16 is pivoted on a fixed stud in the sideframe at 17, and carries a cam roller 18 arranged to ride on theperiphery of the cam 15. The lower end of the bell crank 16 is pivotedto a push bar 19 which extends through a guide slot20 in the front ofthe end frame 1, and, in the rest position of the machine shown inFigures 1 and 2, projects a short distance through said slot contactwith the bent end of the striker bar 12 attached to the friction rollerassembly above described.

The following means are provided for holding a stack of sheets in thetray whilst allowing for automatic single feed.

A pair of sliding paper guides 70, 71 are adjustable to take varyingwidths of paper. For this purpose slots 72, 73 are provided in the traybottom 41, and each guide has a block 74 extending through the slot andthrough a slotted leaf spring 75, which is flexed against the traybottom by means of pin 76 driven through the block 74. The friction ofthe spring 75 is sufficient to hold the paper guide in any adjustedposition.

Friction pads 77 are provided for holding the sides of the stack ofpaper 50 towards the rear end so that only one sheet at a time will bepicked off by the friction feed roller 5. Smotth faced guide blocks 78are provided for guiding the single sheets laterally from the stack,these blocks being placed towards the front end of the paper guides 70,71.

As shown in Fig. 4 each friction pad 77 is a rubber strip secured to asheet metal clip 79 which is bent slightly inward to give the requiredresilience and which has a tongue 80 whereby it may firmly grip theupstanding edge of the sliding guide 70 or 71.

Each guide block 78 is similarly carried on a metal clip 82, but in thiscase the block is of smooth faced material, such as plastic, in orderthat the block shall guide, but not retard, the sheets in their movementfrom the stack.

The operation of the machine is as follows:

The stack of copy paper 50 is placed in the tray, and is laterallystabilized by the friction pads 77 and by the guide blocks 78, whilstthe leading edge of the stack is to the rear of the point of contact ofroller 35 with the wheel 21 by a distance slightly less than the feedstroke d of friction feed roller 5. The friction feed roller 5 rests onthe top sheet of the stack approximately centrally thereof. From therest position of the drum as indicated in the drawing, the drum and thecams rotate in the clockwise direction, whereby bell-crank 16 rotates,during one half of a drum revolution, into the position shown in chainlines, so that the push bar 19 moves the carriage 8 and friction rollerassembly in the reverse direction for a distance d indicated inFigure 1. In the remainder of the drum revolution bell-crank 16, pushrod 19, and the friction feed roller 5 advance to complete the forwardstroke under the tension of return spring 14, during which time thefriction feed roller 5 is locked to the cranked shaft 6, and feeds thetop sheet of copy paper forwardly under the funnel shaped dischargeendof the tray 10 and between the feeding couple constituted by the wheel21 and the roller 35. At this instant the wheel 21 is stationary. Theedge 81 of the gap 37 in the apron assists in guiding the leading edgeof the sheet between the wheel and roller. During the first quarter of afurther revolution of the drum, the linkage consisting of lever 23, link27, lever 29 and lever 33 is actuated by the cam roller 25 to rotate thewheel 21 about 90 degrees in the anti-clockwise direction. During thisphase of the cycle, the first sheet of copy paper is fed forwardly bythe feeding couple constituted by the wheel 21 and the roller 35 towardsthe bight between the drum 2 and the counter-pressure roller 3, whilstat the same time the friction feed roller 5 carried by the tray hasperformed part of another reverse movement over the next sheet of thestack, preparatory to a further forward movement to feed the secondsheet. The timing of the cams is arranged so that there is a minimumdelay between delivery of the sheet from the stack to the feeding couple21, 35 and the commencement of the drive to the said feeding couple toadvance the sheet to the printing couple. When the leading edge of thefirst copy sheet has been gripped between the drum 2 and thecounter-pressure roller 3, the damper operating cam disc 52 depressesthe cam roller 58 and lever 59 against the tension of spring 60, thusallowing the damping pad assembly to move downwardly about the axis P,whereby the front lower edge of the damping pad is pressed against thecopy sheet. Under such conditions damping of the top surface of the copysheet is commenced beginning from an undamped margin corresponding tothe distance between the front edge of the damping pad, when depressed,and the bight of the printing couple. Further revolution of the drumcompletes the feeding of the copy sheet through the printing couple toobtain the impression from the master, whilst the second copy sheet has,in the meantime, been fed between the feeding couple constituted by thewheel 21 and roller 35 by the forward stroke of the friction feed roller5. The dwell portion 53 of the damper operating cam 52 is shaped to givethe required delay in the damper operation with respect to the forwarddisplacement of the copy sheet by the feeding couple 21, 35, and furtheradjustment of this timing is possible by means of the adjusting screw63.

The return motion of the carriage, and of the push rod 19 is effected byspring 14. Although a single return spring may suffice it is preferredto fit also a separate return spring for the push rod, this being shownat 93 (Fig. 2) in the form of a compression spring retained between theside frame 1 and a collar fixed to the rod 19.

In the sheet-feeding mechanism above described, the tray 10 with thefriction feeding device may be removed bodily at any time since there isno positive coupling between the push rod 19 and the frictional feedingroller 5.

As an alternative arrangement Fig. 3 shows a releasable positivecoupling between the rod 19 and the friction feed roller assembly.

The carriage 8 is slidably mounted on the rail 9, as in the abovedescribed construction, but, in place of the striker-bar 12, of Figs. 1and 2, a latch lever 85 is pivoted on the carriage at 86 and cooperateswith a pin 87 on the rod 19 to form a quickly releasable coupling.

A trip lever 89 is secured to the end of the axle of the cranked lever 7extending through the carriage 8, and carries a pin 90 adapted tocooperate with a notch 91 in the latch lever 85. As shown, in thecoupled position, the latch lever 85 is downwardly biased by a spring 88so that a slot 92 engages the pin 87. Automatic feed of the sheets maytherefore be performed in the same way as in the Fig. 1 construction, solong as the latch is engaged on the pin 87.

When hand feeding is desired instead of automatic feeding, the roller 5is swung counter-clockwise into the chain line position, whereby the pin90 rides into the notch 91 and trips the latch lever, causing the slot92 to release the pin 87. The mechanism is held in this position by theweight of the roller retaining the trip lever 89 against a stop 94.

The. pin 87 is clear of the mouth of the slot but not of the lip 95, sothat if the drum is now rotated, the push rod will strike the lip 95 andpush the carriage to the left along the rail 9 and out of, the feedingzone.

If automatic feed is to be resumed, the roller is swung clockwise on tothe stack of sheets and the carriage is pushed forward by hand, wherebythe inclined nose 96 of the latch lever rides over the pin 87, allowingthe slot and pin to engage. During this motion the top sheet is fedforward by the friction roller 5, and automatic feed is taken up fromthis point without interruption.

Any suitable means may be employed for guiding and retaining the feedtray in the machine. A preferred device is indicated in the drawings.Referring to Figs. 1, 2 and 4, grooves 101 are provided in each sideframe 1 and 1a to receive guide plates 102 secured to the bottom of thetray at each side thereof. The laterally projecting edges of the guideplates are separated by a gap 103 through which projects the end of afinger 104 so as to enter a small recess 107 in the respective sideframe. Each finger has a bush 105 whereby it is freely mounted on afixed tie rod 106, and a spring 108 normally retains the finger inposition to lock the tray in the grooves. To remove the tray, thefingers are lifted by means of their lugs 109 so as to remove the clipends from the gaps 103, when the tray can be withdrawn.

The machine and the automatic sheet feeding mechanisirr above describedrepresents only one example of the invention, to which obvious additionsor modifications may be made whilst retaining the benefits of theinvention. For example the machine will normally be fitted'with areceiving tray at the rear side of the printing couple to receive theprinted copy sheets. To conserve space such receiving tray may, be ofthe telescopic type. Further, the details of the sliding carriage u maybe suitably varied; for example the flat guide rail 9 may be replaced bya round section guide rail carrying an alternative form of return springfor the carriage, such spring 'being anchored to the right hand end ofthe guide rail and abutting against the end of the carriage. Whenemploying such a round guide rail a further lateral guide member may benecessary tobalance the cranked shaft 6 and friction roller 5' and toprevent undue pressure on. the stack.

I claim:

1. In a rotary hectographic copying machine having a printing drum and aco-operating counter-pressure roller together forming a printing coupleand a damping pad held in a damping pad frame situated immediatelybefore the printing couple for direct damping of the copy sheets;meansfor feeding copy sheets singly to the printing couple in timedrelation with the rotation of the printing drum comprising a frictionfeeding couple of relatively small width compared with the width of thedrum, said couple being situated underneath the damping pad frameandconsisting of a driven feedwheel' and a freely rotatable roller ofsmaller diameter thanthe feed wheel co-operating therewith, and meansincluding a one-way clutch and an oscillating lever for intermittentlyrotating the feed wheel through part of a revolution to feed the copysheet forward to the line of contact of the drum and the counterpressureroller.

2. In a rotary hectographic copying machine having a printing drum and aco-operating countenpressure roller together forming a printing couple;means for feeding copy sheets singly to the printing couple for eachdrum revolution comprising a friction feeding couple having frictionalcontact with the copy sheet over a central zone of small width comparedwith the width of the drum, said 8 couple consisting of a driven feedwheel and a co-operating freely rotatable roller of smaller diameterthan the feed wheel, means including a one-way clutch and anoscillatinglever for intermittently rotating the feed wheel through partof a revolution to feed the copy sheet forward to the drum, and meansfor resiliently pressing upon the copy sheet and applying volatilespirit thereto after the completion of said forward feeding stroke ofthe feeding couple comprising a movable damping pad and pad framesituated above the feeding couple and a support situated below the padframe and immediately before the printing couple, and cam means actuatedby the drum to lower the pad frame and pad to hold the copy sheet downon the said support during further forward motion of the copy sheetthrough the printing couple.

3. In a rotary hectographic copying machine having a printing drum and aco-opera-ting counter-pressure roller together forming a printing coupleand a damping pad held in a damping pad frame situated immediatelybefore the printing couple for direct damping of the copy sheets; meansfor feeding copy sheets singly to the printing couple in timed relationwith the rotation of the printing drum comprising a friction feedingcouple of relatively small width compared with the width of the drum,said couple being situated underneath the damping pad frame andconsisting of a driven feed wheel and a freely rotatable roller ofsmaller diameter than the feed wheel co-operating therewith, and meansincluding a one-way clutch and an oscillating lever for intermittentlyrotating the feed wheel through part of a revolution to feed the copysheet forward to the line of contact of the drum and the counterpressureroller, said one-way clutch and oscillating lever bringing the feedwheel to rest and then allowing the feed Wheel to rotate freely in thesame. direction through a further portion of a revolution under thetraction of the copy sheet whilst the copy sheet is passing through theprinting couple.

4. In a rotary hectographic copying machine having a printing drum and aco-operating counter-pressure roller together forming a printing coupleand a damping pad for direct damping of copy sheets fed to said printingcouple, the combination of a feed tray having means for aligning theside edges of a stack of sheets and sheet feeding means situated nextbefore the damping pad in the line of feed to the printing couplecomprising a rotary feeding couple having frictional contact with thesheet over a central zone of small width with respect to the printingdrum and comprising a frictional feeding wheel having a shaft supportedin the machine frame, an idler roller of smaller diameter resting on thewheel and disposed at the forward end, of the feed tray, bearings forsaididler feed roller carried in a cantilever plate suspended from thefeed tray and means coupling the wheel shaft to the drum forintermittently driving the feeding couple in timed relation with thedrum so that one forward feeding stroke is performed for each completerevolution of the drum.

5. A machine as claimed in claim 4 including further automatic sheetfeeding means operating in tandem with said rotary feeding elements andcomprising a shaft supported by the feed tray, a friction feed rollercarried on said shaft to rest upon a stack of sheets in said tray, andmeans for. intermittently driving said roller in timed relation with thedrum to feed sheets singly from the stack to the line of contact of saidrotary feeding elements.

6. A machine as claimed in claim 5 wherein the friction feed rollershaft is secured to a sliding carriage which is reciprocated byactuating means driven from the drum shaft, and the friction feed rolleris coupled to the said shaft through a one-way clutch.

7. A machine as claimed in claim 6 wherein the actuating means for thesliding carriage comprises a push rod and an operating cam driven fromthe drum shaft, the said push rod operating upon the sliding carriage tomake the idle stroke of the friction feed roller whilst the feed strokeis performed by a return spring.

8. A machine as claimed in claim 7 wherein the actuating means iscoupled to the sliding carriage by a quickly releasable pin and slotcoupling.

9. A machine according to claim 8 wherein the shaft of the friction feedroller is pivotable to lift the friction feed roller bodily from thestack and simultaneously to release the pin and slot coupling.

10. A machine according to claim 9 wherein a slotted lever is carriedbythe sliding carriage and engages a pin on the push rod and is liftedfrom the said pin by the pivoting of the feed roller shaft and isthereby positioned to be struck by the next succeeding stroke of thepush rod, whereby the carriage is removed from the operative position.

11. In a rotary hectographic copying machine of the kind having aprinting drum and a co-operating counterpressure roller together forminga printing couple and direct damping of the copy sheets by a dampingpad, the combination of a feed tray having means for guiding andaligning the edges of a stack of sheets whilst being fed singly to theprinting couple automatic sheet feeding means for advancing copy sheetssingly from the stack to the printing couple comprising a first sheetfeeding means intermittently driven in timed relation with the printingdrum for advancing a sheet from the stack towards the printing couple,and a second sheet feeding means operating in tandem with the firstsheet feeding means for further advancing the sheet towards the printingcouple, the second sheet feeding means being situated next before thedamping pad in the line of feed to the printing couple so that dampingof the copy sheets is commenced after the copy sheet has been advancedby both of the said sheet feeding means and said second sheet feedingmeans comprising a friction feed wheel, means including a one-way clutchfor intermittently driving said wheel in timed relation with the drumshaft and an idler roller of relatively small diameter resting upon saidfriction vfeed wheel, said wheel and roller co-operating during aforward feeding stroke to grip the copy sheet over a feeding Zone ofsmall width with respect to the width of the drum and to feed the leading edge of the copy sheet forward through a distance slightly greaterthan the distance between the line of contact of the wheel and rollerand the line of contact of the printing couple, said clutch thenallowing the wheel and roller to be freely rotated by the traction ofthe copy sheet drawn therethrough by the printing couple.

References Cited in the file of this patent UNITED STATES PATENTS1,570,592 Parker Jan. 19, 1926 2,064,071 Ma-rchev Dec. 15, 19362,204,715 Wimmer Ian. 18, 1940 2,216,591 Hudson Oct. 1, 1940 2,558,046Geib June 26, 1951 2,594,179 Keil Apr. 22, 1952 2,622,518 Peterson eta1. Dec. 23, 1952 2,633,795 Gerlach Apr. 7, 1953 FOREIGN PATENTS 543,985Germany Feb. 12, 1932

